A politician once said of Germany that it took half the country to control the other half (and he was speaking around 1900, well before either world war). I get the same chilling impression of midseventeenth-century London from The Seeker, a mystery that involves murder, royalist conspiracies, and the terror of speaking one’s mind.

Cover by Henry Steadman (Courtesy Quercus Books, UK).

It’s 1654, and after a fractious, savage civil war, Oliver Cromwell has seized power, employing a vast, pervasive spy network to root out anything he considers subversive. His most ubiquitous, feared agent is Damian Seeker, who seems to know whatever you shouldn’t have done, when, and with whom. So if you’ve spoken against the Lord Protector Cromwell’s joyless, repressive regime; longed for the Stuart monarchy to return; written a poem extolling liberty; or merely sat in the same room as someone who’s done any of these, when The Seeker comes for you–and he will–don’t bother to deny a thing. It’s better not to.

However, what makes Seeker more than an extraordinarily energetic, gifted goon is a passion for truth, no matter where it leads. Consequently, when an assassin fells John Winter, a soldier who enjoyed the Lord Protector’s favor and sat in his inner council, it’s more than a security breach. It’s also a murder case, and finding the killer matters, not only because he could strike again, but–well, because. And from the first, Seeker doubts that Elias Ellingworth is the killer, even if he was discovered near Winter’s body, holding the bloody knife, and even if he’s penned seditious pamphlets.

To find the real murderer, Seeker must follow a sinuous trail that quickly branches in several directions, all of which appear to threaten the regime. Coffee houses, the latest fad in London, are the perfect breeding ground for conspiracy, though they’re also places for free conversation on any topic under the sun. I like how MacLean plays this theme. Cromwell’s followers pretend that they have swept away a tyranny based on birth and replaced it with a temperate government that values merit. But, as Ellingworth insists, the Lord Protector has betrayed the democracy he once professed and instituted a tyranny of his own. That Seeker, a commoner of humble origins, hunts down dissidents to uphold an unjust, autocratic ruler lends the conflict a fitting irony.

Little is known about Seeker’s origins, though, for the man never talks about himself or his feelings, if he even has any. He’s all work. However, Maria Ellingworth, the imprisoned suspect’s sister, interests him, and I doubt I’m giving anything away by saying that the young woman’s naive honesty and directness slowly seep through his defenses. It’s obvious from the get-go, though anything but obvious how it will end.

That’s The Seeker’s greatest strength, I think. Except for a scene or two recounted out of order to withhold a secret, the novel is exceptionally well plotted, no mean trick, given the sheer number of characters. Further, MacLean excels at hiding whether certain key characters are friends or foes, sometimes up until the end. I could have done without a cliché action or two, as when Seeker holds off his men to battle a traitor in single combat, but that’s a minor quibble. I love the period details, which flow seamlessly through the narrative and lend atmosphere. The language does slip occasionally, though; I’m certain no seventeenth-century Englishman would have ever used the phrase liaise with.

Seeker’s also pretty thin as a character, yet he’s the deepest of the lot. Late in the novel–too late, I think–we’re told (not shown) why he’s so loyal to Cromwell, and why he loves order above all. But I’m not entirely persuaded, and I think it would have taken little to establish this in small ways throughout the narrative. Seeker has potential–why is he so fierce, and why does truth matter to him?–but this book doesn’t exploit his inner conflicts. Maybe in future installments, MacLean will show more of him and her other characters.

Nevertheless, I enjoyed The Seeker. In the interest of full reporting, let me add that the novel won the 2015 Crime Writers’ Association Endeavour Dagger for Historical Fiction.

Disclaimer: I obtained my reading copy of this book from the publisher in return for an honest review.